This invention relates to apparatus for transporting horizontal earth boring machines along track ways.
Horizontal earth boring machines are utilized to bore holes or tunnels in the earth for a wide variety of purposes. Such machines are normally moved along and on track ways during the boring operation. It is necessary to periodically move the machines from the front to the rear of the bore pit, for example to install another section of casing or to remove augers from the casing.
Retraction cables associated with winches have often been utilized for such purpose. Because horizontal earth boring machines are quite heavy, tremendous stresses can be placed on the retraction cables and related equipment, creating a potentially dangerous situation.
A relatively recent development has been the use of motor driven wheels in association with the earth boring machine which engage the track way and are utilized to transport the machine in a direction away from the bore. In particular, a retraction system utilizing a hydraulic motor operating track way equipment wheels to retract an earth boring machine is made available by Barbco, Inc., and marketed under the name Fast Track. In that system, a track way engagement wheel is directly driven by a hydraulic motor. A continuous loop drive chain interconnects that track engagement wheel with another; that is, one track engagement wheel is directly driven by the motor and the other track engagement wheel is driven through a drive chain interconnecting the two wheels. This results in uneven forces or loads being applied to the wheels, a factor which lowers the efficiency of the system and promotes wear.
The Fast Trac system is completely disposed within the horizontal earth boring machine to which it is attached and is not readily accessible from outside the machine without partially dismantling the machine. Furthermore, the system is permanently affixed to the frame of the machine. Both of these factors make access to the system, for example to replace bushings, wheels, or other system parts, very difficult and time consuming.
The present invention relates to apparatus for moving an earth boring machine along a track which can readily be installed in modular form on the machine. The module also can readily be removed for maintenance or other purposes. The apparatus can be retrofitted to existing machines with very little structural modification or effort.
In addition, the apparatus incorporates an arrangement for driving first and second track engagement wheels employed therein which evens out the forces applied to the wheels by a hydraulic motor associated therewith. By evening out the load, the lives of bushings and other components of the system are extended.
The apparatus is for moving an earth boring machine along a track, the earth boring machine defining an opening.
The apparatus includes a module for releasable connection as a unit to the earth boring machine. The module comprises a support plate, a housing connected to the support plate, extending from a side of the support plate and defining a housing interior, a motor having a drive shaft attached to the support plate, at least one track engagement wheel rotatably mounted in the housing interior and projecting downwardly from the housing, and mechanical linkage interconnecting the at least one track engagement wheel and the drive shaft.
Releasable connector means is provided for releasably mounting the module on the earth boring machine with the housing projecting inwardly into the earth boring machine at the opening.
In the preferred embodiment disclosed herein, first and second track engagement wheels are rotatably mounted in the housing interior and project downwardly from the housing. The first and second track engagement wheels are spaced from one another. The mechanical linkage includes an endless drive element interconnecting the first and second transport wheels and the drive shaft.